Electric furnace



April 8, 1930.

E. BORNAND ET AL ELECTRIC FURNACE Filed Nov. 24, 1928 INVENTOR. I fav wmg QM/Z ScM ze BY WM r A TTORNEYS.

Patented Apr. 8, 1930 UNITED STATES EMILIEN BORINAND AND HANS ARNOLD ELECTRIC Application filed November 24, 1923, Serial No.

add to a metal bath a substance which is to be incorporated with this bath. In many cases this substance is lightertha-n the metal of the bath and when added thereto in the form of slag floats on the surface of the loath. When the additional substance is molten or volatilized by the electric are it does not get in intimate contact with the bath and therefore the reaction is very slow and incomplete.

The object of this invention is to provide an electric furnace adapted to improve and accelerate the reaction between the slag and the metal bath and for this purpose the electric furnace according to the invention comprises a furnace chamber receiving the metal to be treated, and a vertically movable electrode which may be lowered into the molten metal, the bottom face of said electrode having a cavity provided therein, so that when the electrode is inserted into the metal bath, it carries a part of the additional substance floating on top of the bath into the interior thereof and maintains it there until this substance is volatilized and forced to traverse the larger part of the bath, thereby enabling a quick and complete reaction.

The accompanying drawing illustrates a vertical section through an electric furnace according to the invention.

The furnace shown is supplied with threephase electric current and comprises a furnace chamber i, an electrode 5 penetrating the bottom wall of the chamber and an electrode 6 capable of being vertically moved. This electrode consists of a body 8 of electrically insulating and refractory material and three cores 7 of carbon. The bottom face of the electrode 6 has a downwardly projecting marginal portion whereby a cavity 91 is formed.

Supposing an aluminium and magnesium alloy is to be manufactured in this furnace, aluminium is first molten in the furnace chamber by means of the are formed between the upper electrode 6 and the metal in the furnace. Then the electrode is pulled up above SGHLAEEFER, GE GENEVA, :SWITZERLAND Bummer:

$531,740, and in Switzerlandi December 8, 1927.

the furnace chamber and magnesium isadded to aluminium in the chamber. Since magnesium is the lighter metal it floats on top of the aluminiun'i. Now the electrode 6 is lowered and volatilized and forced to traverse the larger part of the aluminium bath. It is evident that the electrode 6 can be raised above the bath and lowered again several times, so that nearly all of the magnesium is forced to traverse the larger part of the aluminium bath. In this way an intimate mixture of the aluminium and magnesium and therefore a quick and complete reaction is obtained.

Instead of using a single electrode with several cores, a plurality of single core electrodes could be used and a slight oscillating movement could be imparted to the furnace so that all of the metal bath passes between the electrodes 5 and 6.

W e claim 1. An electric furnace for metal treating, comprising a furnace chamber adapted to receive the metal to be treated, and a vertically movable electrode adapted to be inserted into the molten metal, the bottom face of said electrode having a cavity formed therein for receiving an additional substance to be incorporated with the molten metal.

2. An electric furnace for metal treating, comprising a furnace chamber adapted to receive the metal to be treated, and a vertically movable electrode formed of a body of electrically insulating and refractory material having a plurality of conducting cores and adapted to be inserted into the molten metal, the bottom face of said electrode having a cavity formed therein for receiving an additional substance to be incorporated with the molten metal.

3. An electric furnace for metal treating,

again and inserted into the molten metal.

comprising a furnace chamber adapted to receive the metal to be treated, and a Vertically movable electrode formed of a body of refractory and electrically insulating material having a plurality of conducting cores and adapted to be inserted into the molten metal, the bottom face of said electrodes having a downwardly projecting marginal portion, whereby a cavity is formed adapted to bring an additional substance which is lighter than said metal into the interior of the molten metal.

In testimony whereof we affix our signatures.

EMILIEN BORNAND.

HANS ARNOLD SOHLAEPFER. 

